MICROBEAD TRAPPING



2012-2013

Microbead Trapping Device:

Vasileiou Georgios

(georgiosvasileiou@hotmail.com)

Linkedin


National Technical University of Athens
Mechanical Engineers
Department of Bioengineering

Special Thanks,
i would like to thank all members of the lab for their help and especially George Kanakaris who helped me with his advice.


1) Micro-Beads & Bead-Based Sandwich ELISA:



Micro-Bead Trapping Device refers to magnetic micro-beads (typical diameter of about 5 microns) used in Bead-Based Sandwich ELISA. The microbeads contain 2-4% Fe which is responsible for their magnetic abilities.


In typical ELISA procedures we are able to identify and count one single protein at a time. In Bead-Based Sandwich ELISA the use of magnetic micro-beads adds multiplexability which means we are able to identify up to 100 different proteins (in reality practical reasons prevent us from doing so).

How?

The beads are identified by a fluorescent dye, being impregnated with the mixture of red and infrared dyes in 10 different concentrations each. Therefrom 100 different colour identities are feasible.

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MICRO-BEAD COLOUR LABEL



ELISA .jpg
BEAD-BASED SANDWICH ELISA


2) Device Specifications


  • The beads along with the solvent containing the proteins is put inside an eppendorf tube.
  • Eppendorf tubes must touch permanent magnets so that the beads stick to the surface, therefore being able to change the solvent according to the ELISA procedures.
  • The device must be able to adjust to a shaker as well as to a shonicator and float. Both the shaker and the sonicator are used to facilitate the diffusion processes. Sonication is also needed to split the beads (magnetic beads have the tendency to form sets of beads tight to each other-obviously we don't want this in our experiments).
  • The pippet's tips -used to remove the solvents from the eppendorf tubes- are spaced 9cm. Eppendorf tube's diameter is about 10.7mm therefore eppendorf tubes must be spaced 18mm.


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LAB EQUIPMENT- PIPETTE TIP & EPPENDORF TUBE






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LAB EQUIPMENT-SONICATOR





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LAB EQUIPMENT-PIPETTE





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LAB EQUIPMENT-SHAKER (VORTEX)





3) ALTERNATIVE CONCEPT DESIGNS


aseenn.JPG
CONCEPT DESIGN 1




Assem2.JPG
CONCEPT DESIGN 2




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CONCEPT DESIGN 3






The designs presented above are only displayed to show different aspects of the designing process


During the designing process aspects of the exact constraint theory were used.


4) FINAL DESIGN

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Micro-Bead Trapping Device



plotiras1.jpg
Main device body with float



I may alter the float's geometry should we decide that the float is to be consumable.


pano plate qe.jpg
UPPER PLATE



MIDDLE FRAME.jpg
FRAME




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MIDDLE PLATE





5) MATERIALS USED



Upper plate & frame: compact polycarbonate sheet
Legs, dowel pins, lower plate and middle part : aluminum alloys 2011 T6 and 7075 T651
Float: closed-cell PU foam, density=0.037g/cm^3


6) PROCESSES

  • Legs & dowel pins: turning
  • Upper plate, frame & lower plate: waterjet cutter
  • Middle part: cnc milling and drilling
  • Numbers on upper plate: engraving


Specifically for the middle part, lacking a 4th axis on the lab's cnc milling center we used a special clamp.
The clamp is demonstrated below.


clamp.JPG
rotating clamp